Safety ball socket connector for electric plugs



ug- 10, 1965 J. s. cARPlNoNE SAFETY BALL SOCKET CONNECTOR FOR ELECTRICPLUGS Filed Oct. 28. 1963 2 Sheets-Sheet 1 INV EN TOR. .Josep/7{fa/Winona Aug. l0, 1965 J. s. cARPlNoNE SAFETY BALL SOCKET CONNECTORFOR ELECTRIC PLUGS Filed 0G12. 28, 1953 2, Sheets-Sheet 2 I N VEN TOR../asep fCczf/o//m/ze United States Patent O masses SAFETY BALL SCKETCNNECTR FR ELECTREC PLUGS Joseph S. Carpinone, Zlld W. 35th St., NewYork, NSY. Filed 9ct. 23, 1963, Ser. No. 319,363 8 Claims. (El. 339-403)This invention concerns an improved electrical connector or receptaclewith spring loaded ball grip and contact means.

According to the invention there is provided an electrical connector orreceptacle especially adapted for attachment to wires at the end of acable enclosed in a metal shield. The electrical connector has socketcontact members for receiving prongs of a terminal plug. In order toeffect a positive frictional grip on the prongs when inserted in thecontact members of the receptacle, to insure electrical continuitybetween the prongs and Contact members at all times, and to preventsparking between the prongs and contact members, there is provided aspring and ball assembly in the electrical connector.

In accordance with the invention, the connector or receptacle isprovided with an auxiliary lateral block in which spring and ballassemblies are mounted. Each of the contact members in the receptaclehas a concave seat formed therein through which a ball loaded by aspring can extend for engaging one of the prongs of the plug. The ballexerts lateral pressure on the prong to insure complete and continuouselectrical continuity between the prong and contact member. ln addition,the ball serves as an electrical circuit element to bridge points of theprong and contact member. The net results are lowered contactresistance, and prevention or" sparking and of erratic discontinuouscontacts between the prongs of the plug and the socket members of thereceptacle.

It is therefore one object of the invention to provide an electricalreceptacle for a plug, in which the receptacle has spring loaded ballgrip and Contact assemblies associated with contact members in thereceptacle to engage prongs of the plug.

A further object is to provide an electrical receptacle as described,wherein the spring and ball assemblies are housed in a block laterallymounted on the receptacle.

Another object is to provide an electrical receptacle as describedwherein the assemblies are provided with adjustable means ror varyingtension in the springs and pressure on the balls of the assemblies.

For further comprehension of the invention, and of the objects andadvantages thereof, reference will be had to the following descriptionand accompanying and to the appended claims in which the various novelfeatures of the invention are more particularly set forth.

In the accompanying drawings forming a material part of this disclosure:

FIG. 1 is a perspective View of an electrical receptacle embodying theinvention, shown with part of an associated plug, and with part of anattached shielded cable.

FlG. 2 is a side view of the receptacle with part of the plug.

FIG. 3 is a front end view of the receptacle.

FIG. 4 and FIG. 5 are sectional views taken on lines 4 4 and 5-5,respectively, of FIG. 3.

FIG. 6 is a sectional view taken on line 6 6 of FIG. 4.

FIG. 7 is an enlarged fragmentary sectional view similar to a portion ofFlG. 6, with a prong of a plug shown inserted in the receptacle.

FIG. 8 is an enlarged perspective view of a contact member of thereceptacle.

FIG. 9 is an exploded perspective view or a body pordrawings,

tion of the receptacle shown in an inverted position, with associatedparts.

HG. 1() is a perspective view of a block employed in the receptacleshown with parts of the spring and ball assemblies.

FG. 11 is an exploded perspective view of parts of the receptacle.

Referring to the drawings, there is shown in FIGS. 1-7 the receptacle2li including an elongated generally rectangular body portion 22 with anauxiliary rectangular block 2d. The block is equal in width to that ofbody portion 22 but is shorter than the body portion.

The body portion 2.2 has dat opposite sides 25, 26. In the underside .26shown to best advantage in FIGS. 4, 5 and 9 is a rather large recess 27communicating with a large hole 2S which extends through the bodyportion to open at upper side 25. Wires W extending out of one end of ametal shield S can be passed through hole 2S and recess 27 to be engagedby screws 29 and washers 30 at rear ends 31 of contact members 32. Theends 31 of the contact members have threaded holes 33 to receive thescrews 29; see FIGS. 4 and 8. The recess 27 is covered by a removabledat plastic plate 34 having holes 35 through which extend screws 35. Thescrews are seated in threaded holes 3S, 39 and itl formed at the endcorners and near the center of the body portion 22 at side 26.

The body portion 32 has two cylindrical bores i2 extending inwardly fromfront end 43. in these bores are embedded two generally cylindricalhollow contact members .32. The contact members are formed withdiametrally slit arcuate forward sections id serving as spring fingerstl .and delining cylindrical passages PP into which the prongs of a plugP can be axially inserted. The rear ends El of the contact members aregenerally rectangular and extend rearwardly to be exposed at the recess27 for attachment of wires W to the contact members.

The body portion 22 has two holes de, 47 extending through the bodyportion. Screws d8 and #i9 can be inserted through these holes. Theholes are countersunk at side 26 to receive the conical heads of thescrews. The head of screw will be concealed by plate 34 when it isattached by screws 36 to body portion 22. The head of screw i9 will beexposed at side 26; see FIG. 5.

Auxiliary bloeit 24.- is juxtaposed to side 25 of body portion Z2 whenthe receptacle is assembled. The front end 5d of the block is ilush withand in registration `with the front end d3 of the body portion 22. Theblock has opposite dat sides 5l, S2. Two spaced holes 53a, 53b extendthrough the block and are located in registration with holes 46, 457 otbody portion 22. The screws 48, 49 extend through holes 53, 53". Thefree ends of the screws engage in holes 54:1 of a shield clamp 55. Theseholes can be threaded to engage the screws and locknuts S6 can bescrewed on the ends of the screws projecting through holes 53. The clamphas arcuate lingers 57 engaged by screws 58 for embracing and holdingshield S in axial alignment with hole 2d in body portion 22.

The block Z4 is formed with two blind end cylindrical bores 60 extendinginwardly of the block from side Sil. Seated in these bores are springand ball assemblies 65 each including a cylindrical internally threadedsleeve ed; see FIGS. 4, 7, l0 and ll. A set screw 67 is adjustablyscrewed into one end of sleeve 66. The screw bears axially on a coilspring 63 which in turn bears on a metal ball 69.

Body portion 22 is formed with two lateral holes or bores 7) registeringwith bores 60. Sleeves 66 seat in bores '79. Bores '75l are axiallyperpendicular to the axes of contact members 32 and are aligned with thediametral slits or spaces SL between sections 44 ot the contact members32. The bores '70 extend inwardly from side 25 and terminate in a planesubstantially tangential to the upper sides of the contact members.Lateral holes 72 with conical edges are formed in axial alignment withbores 60 and 70 at facing edges of slits SL and serve as conical seatsfor the lower portions of the balls 69 when the prongs 45 of the plugare removed from the receptacle. The balls then project into passages PPbetween spring fingers 44.

When the prongs 45 are inserted in the passages PP of the socket membersof the receptacle as shown on an enlarged scale in FIG. 7, the springsare compressed and the balls are slightly retracted or pushed outwardly.It will be noted in FIG. 7 that the pressure of the springs on the ballsis transmitted to the prongs 45 forcing and holding them in firm andcontinuous Contact with the sections 44 of the contact members atcontact points CPI and CP2. In addition, each ball 69 provides anothercircuit path CP3 between one of the contact sections 44 and the insertedprong 45. This occurs because the ball will tend to roll slightlylaterally off the top dead center of the prong under pressure of thespring to become securely seated in conical hole 72 and bridge section44 and prong 45. The two balls 69, which are continuously spring pressedagainst the prongs, prevent the prongs from shaking laterally in orslipping axially out of the receptacle. The continuous contact betweenthe prongs and socket members maintained by the spring loaded ballsprevents sparking. In addition, the circuit paths CP3 provided by theballs 69 reduce the inherent electrical contact resistance between theprongs and socket members. The spring fingers may also grip the sides ofVthe prongs if the prongs are not too narrow.

blies securely on the body portion 22 by the screws 48,

49 locked by nuts 56. The entire receptacle can be very quicklyassembled, or disassembled, when required. Since the recess 27 isuncovered by removing plate 34, it is not necessary to disturb the block24 and its contents to attach and detach wires W from the receptacle.

The block 24 and body portion 22 may be made of rigid plastic insulationmaterial. The several bores may be formed at the time these plasticparts are molded or subsequently. The holes 72 in the contact memberscan be made prior or subsequent to assembly or embedding of the contactmembers in the body portion 22 of the receptacle.

While I have illustrated and described the preferred embodiment of myinvention, it is to be understood that I do not limit myself to theprecise construction herein disclosed and that various changes andmodifications may be made within the scope of the invention as definedin the appended claims.

Having thus described my invention, what l claim as new, and desire tosecure by United States Letters Patent 1. An electrical connector for aplug having a pair of prongs, comprising a rectangular body portionhaving a pair of parallel first bores extending inwardly from one end ofsaid body portion, a pair of cylindrical hollow contact members axiallydisposed in said bores and having axial passages for receiving saidprongs respectively, said body portion having a recess at the other endthereof, said contact members having ends thereof disposed in andexposed at said recess, said body portion having a first lateral holecommunicating with said recess for passing wires into the recess toconnect with said ends of the contact members, each of said contactmembers having a lateral hole therein between its opposite ends, saidbody portion having a pair of other lateral holes respectively alignedaxially with the. lateral holes in the contact members and communicatingtherewith, a rectanguar block, screws extending through said bodyportion and block to hold the block against one side of said bodyportion, a clamp for a cable shield engaged by said screws at one sideof said block, said clamp having clamp fingers for engaging said cableshield aligned with the first lateral hole for passing wires from saidshield into said recess, said block having a pair of blind boresrespectively axially aligned and registering with said other lateralholes, a compressed coil spring in each of said blind bores extendinginto one of said other lateral holes, a ball at one end of each springengaged by the spring and pressed into one lateral hole in a contactmember, said balls projecting into the passages in said contact members,whereby the springs contract and the balls are retracted when the prongsof the plug are inserted into said contact members while the spring holdthe balls under pressure to keep the prongs pressed laterally intocontact with the contact members.

2. An electrical connector for a plug having a pair of prongs,comprising a rectangular body portion having a pair of parallel firstbores extending inwardly from one end of said body portion, a pair ofcylindrical hollow contact members axially disposed in said bores andhaving axial passages for receiving said prongs respectively, said bodyportion having a recess at the other end thereof, said contact membershaving ends thereof disposed in and exposed at said recess, said bodyportion having a first lateral hole communicating with said recess forpassing wires into the recess to connect with said ends of the contactmembers, each of said contact members having a lateral hole thereinbetween its opposite ends, said body portion having a pair of otherlateral holes respectively aligned axially with the lateral holes in thecontact members and communicating therewith, a rectangular block, screwsextending through said body portion and block to hold the block againstone side of said body portion, a clamp for a cable shield engaged bysaid screws at one side of said block, said clamp having clamp fingersfor engaging said cable shield aligned with the rst lateral hole forpassing wires from said shield into said recess, said block having apair of blind bores respectively axially aligned and registering withsaid other lateral holes, an internally threaded sleeve in each of theblind bores extending into one of said other lateral holes, a coilspring in each of the sleeves, a screw in each of the sleeves at one endthereof bearing on one end of the coil spring for adjusting compressionthereof, a ball at the other end of each spring and engaged thereby,said balls being pressed into the lateral holes in the contact membersby the compressed springs with the balls extending into the passages inthe contact members, whereby the springs contract and the balls areretracted when the prongs of the plug are inserted into the contactmembers While the springs hold the balls under pressure to keep theprongs pressed laterally into contact with the contact members.

3. An electrical connector for a plug having a prong, comprising arectangular body portion made of insulation material and having a firstbore extending inwardly from one end of said body portion, a cylindricalhollow contact member axially disposed in said bore and having an axialpassage for receiving said prong, said body portion having a recess atthe ,other end thereof, said contact member having one end thereofdisposed in and exposed at said recess, said body portion having a firstlateral hole communicating with said recess for passing a wire into therecess to connect with said end of said contact member, said contactmember having a lateral hole therein between its ends, said body portionhaving another lateral hole aligned axially with the lateral hole in thecontact member and communicating therewith, a rectangular block made ofinsulation material, screws extending through said body portion andblock and holding the block against one side of said body portion, aclamp for a cable shield engaged by said screws at one side of saidblock, said clamp having fingers for engaging said cable shield alignedwith the first lateral hole for passing a wire from said cable shieldinto said recess, said block having a blind bore axially aligned andregistering with said other escasas lateral hole, a compressed coilspring in said blind bore and extending into said other lateral hole, aball at one end of the spring engaged by the spring and pressed into thelateral hole in the contact member, said ball projecting into saidpassage in the contact member, whereby the spring contracts and the ballis retracted when the prong of the plug is inserted into the contactmember while the spring holds the ball under pressure to keep the prongpressed laterally into contact with the contact member to elect oneelectrical connection, and whereby the ball serves as a circuit elementto complete a second electrical connection between the prong and contactmember to lower electrical contact resistance between the prong andcontact member, to prevent sparking between the prong and contactmember, and to hold the prong frictionally in said contact member.

4. An electrical connector for a plug having a prong, comprising arectangular body portion made of insulation material and having a lirstbore extending inwardly from one end of said body portion, a cylindricalhollow contact member axially disposed in said bore and having an axialpassage for receiving said prong, said body portion having a recess atthe other end thereof, said contact member having one end thereofdisposed in and exposed at said recess, said body portion having a firstlateral hole communicating with said recess for passing a wire into therecess to connect with said end of said contact member, said contactmember having a lateral hole therein between its ends, said body portionhaving another lateral hole aligned axially with the lateral hole in thecontact member and communicating therewith, a rectangular block made ofinsulation material, screws extending through said body portion andblock and holding the block against one side of said body portion, aclamp for a cable shield engaged by said screws at one side of saidblock, said clamp having lingers for engaging said cable shield alignedwith the first lateral hole for passing a wire from said cable shieldinto said recess, said block having a blind bore axially aligned andregistering with said other lateral hole, a threaded sleeve in the blindbore and other hole, a coil spring in said sleeve, a screw adjustablydisposed in said sleeve and bearing on one end of said spring tomaintain the same in a compressed condition, an electrically conductiveball at the other end of the spring engaged by the spring and pressedinto the lateral hole in the contact member, said ball projecting intosaid passage in the contact member, whereby the spring contracts and theball is retracted when the prong of the plug is inserted into thecontact member while the spring holds the ball under pressure to keepthe prong pressed laterally into contact with the contact member toeiiect one electrical connection, and whereby the ball serves as acircuit element to complete a second electrical connection between theprong and contact member to lower electrical contact resistance betweenthe prong and contact member, to prevent sparking between the prong andcontact member, and to hold the prong frictionally in said contactmember.

5. An electrical connector for a plug having a prong, comprising arectangular body portion having a first bore extending inwardly from oneend thereof, a cylindrical hollow contact member disposed in said borein axial alignment therewith, said contact member having an axialpassage to receive said prong, said contact member having a lateral holetherein, said body portion having a lateral other hole communicatingwith and axially aligned with the hole in the contact member, arectangular block, means securing said block to one side of said bodyportion, said block having a lateral blind bore therein axially alignedwith the holes in the contact member and body portion, a threaded sleevein the blind bore and other hole, a coil spring in vsaid sleeve, a setscrew adjustably disposed in said sleeve and bearing on one end of saidspring to maintain the same in a compressed condition, an electricallyconductive ball engaged at the other end of said spring and disposed insaid other hole, said ball being pressed by said spring into the hole inthe contact member, said ball extending into the passage in the contactmember, whereby the spring contracts and the ball is retracted when saidprong of said plug is inserted into said contact member while the springholds the ball under pressure to keep the prong pressed laterally intocontact with said contact member to complete one circuit path, andwhereby said ball serves as a circuit element to complete an auxiliarycircuit path between said prong and said contact member to lower contactresistance between the prong and contact member to prevent sparkingbetween the prong and contact member, and to hold the prong frictionallyin said contact member, said contact member being partially splitlongitudinally to define two spring lingers for frictionally grippingsaid prong, said lateral hole being formed on adjacent edges of the twospring tingers and having a generally conical shape for retaining saidball therein.

6. An electrical connector for a plug having a pair of prongs,comprising a rectangular body por-tion having a pair of parallel firstbores extending inwardly from one end of said body portion, a pair ofcylindrical hollow contact members axially disposed in said bores andhaving axial passages for receiving said prongs respectively, said bodyportion having a recess at the other end thereof, said contact membershaving ends thereof disposed in and exposed at said recess, said bodyportion having a lirst lateral hole communicating with said recess forpassing wires into the recess to connect with said ends of the contactmembers, each of said contact members having a lateral hole thereinbetween its opposite ends, said body portion having a pair of otherlateral holes respectively aligned axially with the lateral holes in thecontact members and communicating therewith, a rectangular block, screwsextending through said body portion and block to hold the block againstone side of said body portion, a clamp for a cable shield engaged bysaid screws at one side of said block, said clamp having clamp lingersfor engaging said cable shield aligned wit-h the first lateral hole forpassing wires from said shield into said recess, said block having apair of blind bores respectively axially aligned and registering withsaid other lateral holes, a compressed coil spring in each of said blindbores extending into one of said other lateral holes, a ball at one endof each spring engaged by the spring and pressed into one lateral holein a contact member, said balls projecting into the passages in saidcontact members, whereby the springs contract and the balls areretracted when the prongs of the plug are inserted into said contactmembers while the springs hold the balls under pressure to keep theprongs pressed laterally into contact with the Contact members, saidcontact members each being partially split longitudinally to define twospring lingers for frictionally gripping said prongs, the lateral holesin the contact members being formed on adjacent edges of the springlingers and having generally conical shapes to deline conical seats forretaining the balls therein.

7. An electrical connector for a plug having a pair of prongs,comprising a rectangular body portion having a pair of parallel firstbores extending inwardly from one end of said body portion, a pair ofcylindrical hollow contact members axially disposed in said bores andhaving axial passages for receiving said prongs respectively, said bonyportion having a recess at the other end thereof,

fsaid contact members having ends thereof disposed in and exposed atsaid recess, said body portion having a first lateral hole communicatingwith said recess for passing wires into the recess to connect with saidends of the contact members, each of said contact members having alateral hole therein between its opposite ends, said body portion havinga pair of other lateral holes respectively aligned axially with thelateral holes in the contact members and communicating therewith, arectangular block, screws extending through said body portion and blockto hold the block against one side of said body portion,

a clamp for a cable shield engaged by said screws at one side of saidblock, said clamp having clamp fingers for engaging said cable shieldaligned with the irst lateral hole for passing wires from said shieldinto said recess, said block having a pair of blind bores respectivelyaxially aligned and registering with said other lateral holes, aninternally threaded sleeve in each of the blind bores extending into oneof said other lateral holes, a coil spring in each of the sleeves, ascrew in each of the sleeves at one end thereof bearing on one end ofthe coil spring for adjusting compression thereof, a ball at the otherend of each spring and engaged thereby, said balls being pressed intothe lateral holes in the Contact members by the compressed springs withthe balls extending into the passages in the contact members, wherebythe springs contract and the balls are retracted when the prongs of theplug are inserted into the contact members while the springs hold theballs under pressure to keep the prongs pressed laterally into contactwith the contact members, said contact members each being partiallysplit longitudinally to dene two spring fingers for frictionallygripping said prongs, the lateral holes in the Contact members beingformed on adjacent edges of t-he spring fingers and having generallyconical shapes to define conical seats for retaining the balls therein.

8. An electrical connector for a plug having a prong, comprising arectangular body portion made of insulation material and having a irstbore extending inwardly from one end of said body portion, a cylindricalhollow contact member axially disposed in said bore and having an axialpassage for receiving said prong, said body portion having a recess atthe other end thereof, said contact member having one end thereofdisposed in and exposed at said recess, said body portion having a rstlateral hole communicating with said recess for passing a wire into therecess to connect with said end of said contact member, said contactmember having a lateral hole therein between its ends, said body portionhaving another lateral hole aligned axially with the lateral hole in thecontact member and communicating therewith, a rectangular block made ofinsulation material, screws extending through said body portion andblock and holding the block against one side of said body portion, aclamp for a cable shield engaged by said screws at one side of saidblock, said clamp having fingers for engaging said cable shield alignedwith the first lateral hole for passing a wire from said cable shieldinto said recess, said block having a blind bore axially aligned andregistering with said other lateral hole, a threaded sleeve in the blindbore and other hole, a coil spring in said sleeve,.a screw adjustablydisposed in said sleeve and bearing on one end of said spring tomaintain the same in a compressed condition, an electrically conductiveball at the other end of the spring engaged by the spring and pressedinto the lateral hole in the contact member, said ball projecting intosaid passage in the contact member, whereby the spring contracts and theball is retracted when the prong of the plug is inserted into thecontact member While the spring holds the ball under pressure to keepthe prong pressed laterally into contact with the contact member toeiect one electrical connection, and whereby the ball serves as acircuit element to complete a second electrical connection between theprong and contact member to lower electrical contact resistance betweenthe prong and contact member, to prevent sparking between the prong thecontact member, and to hold the prong frictionally in said contactmember, said contact member being partially split longitudinally to denetwo spring fingers for frictionally gripping said prong, said lateralhole being formed on adjacent edges of the two spring fingers and havinga generally conical shape for retaining said ball therein. v

References Cited bythe Examiner UNITED STATES PATENTS Re. 18,193 9/31Kollath 339-103 X 1,160,619 11/15 Klein. 1,422,257 7/22 Douglas 339-254X 1,518,733 12/24 Eckstein 339-210 X 1,629,086 5/27 Wohl et al 339-210 X2,088,845 8/37 De Mask 339-191 X FOREIGN PATENTS 499,285 11/50 Belgium.954,070 12/56 Germany. 379,810 9/32 Great Britain.

ALBERT H. KAMPE, Primary Examiner.

JQSEPH D. SEERS, Examiner.

1. AN ELECTRICAL CONNECTOR FOR A PLUG HAVING A PAIR OF PRONGS,COMPRISING A RECTANGULAR BODY PORTION HAVING A PAIR OF PARALLEL FIRSTBORES EXTENDING INWARDLY FROM ONE END OF SAID BODY PORTION, A PAIR OFCYLINDRICAL HOLLOW CONTACT MEMBERS AXIALLY DISPOSED IN SAID BORES ANDHAVING AXIAL PASSAGES FOR RECEIVING SAID PRONGS RESPECTIVELY, SAID BODYPORTION HAVING A RECESS AT THE OTHER END THEREOF, SAID CONTACT MEMBERSHAVING ENDS THEREON DISPOSED IN AND EXPOSES AT SAID RECESS, SAID BODYPORTION HAVING A FIRST LATERAL HOLE COMMUNICATION WIT SAID RECESS FORPASSING WIRES INTO THE RECESS TO CONNECT WITH SAID ENDS OF THE CONTACTMEMBERS, EACH OF SAID CONTACT MEMBERS HAVING A LATERAL HOLE THEREINBETWEEN ITS OPPOSITE ENDS, SAID BODY PORTION HAVING A PAIR OF OTHERLATERAL HOLES RESPECTIVELY ALIGNED AXIALLY WITH THE LATERAL HOLES IN THECONTACT MEMBERS AND COMMUNICATING THEREWITH, A RECTANGULAR BLOCK, SCREWSEXTENDING THROUGH SAID BODY PORTION AND BLOCK TO HOLD THE BLOCK AGAINSTONE SIDE OF SAID BODY PORTION A CLAMP FOR A CABLE SHIELD ENGAGED BY SAIDSCREWS AT ONE SIDE OF SAID BLOCK, SAID CLAMP HAVING CLAMP FINGERS FORENGAGING SAID CABLE SHIELD ALIGNED WITH THE FIRST LATERAL HOLE FORPASSING WIRES FROM SAID SHIELD INTO SAID RECESS SAID BLOCK HAVING A PAIROF BLIND BORES RESPECTIVELY AXIALLY ALIGNED AND REGISTERING WITH SAIDOTHER LATERAL HOLES, A COMPRESSED COIL SPRING IN EACH OF SAID BLINDBORES EXTENDING INTO ONE OF SAID OTHER LATERAL HOLES, A BALL AT ONE ENDOF EACH SPRING ENGAGED BY THE SPRING AND PRESSED INTO ONE LATERAL HOLEIN A CONTACT MEMBER, SAID BALLS PROJECTING INTO THE PASSAGES IN SAIDCONTACT MEMBERS, WHEREBY THE SPRINGS CONTRACT AND THE BALLS ARERETRACTED WHEN THE PRONGS OF THE PLUG ARE INSERTED INTO SAID CONTACTMEMBERS WHILE THE SPRING HOLD THE BALLS UNDER PRESSURE TO KEEP THEPRONGS PRESSED LATERALLY INTO CONTACT WITH THE CONTACT MEMBERS.